Angelina Jolie has visited the tiny Italian island of Lampedusa and thanked its residents for welcoming in the estimated 20,000 migrants who arrived after fleeing unrest in Tunisia and Libya.

Angie, a goodwill ambassador for the UN High Commissioner for Refugees, toured a migrant holding centre, chatted with some refugees and then participated in a ceremony at Lampedusa's memorial for migrants lost at sea as part of commemorations for World Refugee Day.

"You cannot imagine what you represented to all those people this year who were looking desperately for help," Jolie was quoted as saying by the ANSA news agency.

Angelina had earlier travelled to Turkey's border with Syria to meet some of the thousands of Syrian refugees who have fled their government's bloody crackdown on dissent.

UN refugee chief Antonio Guterres was also on hand in Lampedusa to urge Europe to continue keeping its doors open to refugees. Italy's centre-right government has begrudgingly accepted the migrants, but has also struck deals with Tunisia and the Libyan opposition to return those who do not qualify for asylum.

Mr Guterres said the debate in Europe about immigration "doesn't correspond to the reality", given that the number of African migrants who have arrived in Europe is a fraction of the numbers who have gone elsewhere.